The present invention relates to a self-centering jig for planar articles, such as, for example, cabinet drawer fronts. The self-centering jig may be used to accurately and precisely mark and/or drill such planar articles. The construction and operation of the present invention will be described in relation to the cabinetry making art, although those of ordinary skill in the art will recognize the invention has utility in other fields where highly accurate and repetitive marking and/or drilling is required.
One of the required tasks in the cabinetry making art is to accurately drill holes in a drawer front to permit the installation of drawer pulls or knobs. The location and number of holes will depend on the size of the drawer front and the number of pulls or handles to be fitted to the drawer front.
Manual location and drilling of such holes is dependent on the skill and care of the individual worker. Thus, the art has sought to ensure a minimum standard of accuracy is achieved by the use of various tools such as templates. See, for example, U.S. Pat. No. 2,203,992 to Lutz, which describes a template-type marking instrument for drawer pulls. Similar gauges and templates are described in U.S. Pat. Nos. 1,545,424; 2,197,505; 2,582,606; 2,807,095; 3,197,874; 4,257,166; 4,270,276 and 4,791,732. Although such templates do improve the consistency of individual workers, these tools all depend on manual initial adjustment.
The problem of manual initial adjustment is partially addressed in U.S. Pat. No. 2,842,860 to Gray, which discloses an automatically horizontally centering drawer handle marking device. The device includes a horizontal support bracket adapted to receive the top edge portion of the drawer. Horizontally extending positioning arms engage opposite side edges of the drawer front. Movement of one arm causes automatic movement of the other arm such that the device will automatically be centered between the two sides. Selected openings are provided from which a punch can be inserted to mark the locations at which screws are to extend into the drawer.
A similar device is disclosed in U.S. Pat. No. 3,583,823 to Eaton et al, which discloses an adjustable fixture for locating hole locations for various size draw pulls on various width drawers. The fixture has an elongated body with interconnected extendable arms having abutment means on the ends thereof for engaging the sides of a drawer to align the centerline of the fixture at the midpoint between the drawer sides. Guide apertures are formed in interconnected blocks that move uniformly in opposite directions to adjust the spacing between the guide apertures to accommodate various size drawer pulls. The adjustable fixture has an adjustable support means and distance scale for vertically positioning the fixture on a drawer face.
Both Gray and Eaton et al depend on manual vertical positioning of the apparatus, which provides a possible source of error and also reduces productivity by requiring additional operator time.
An object of the present invention is to provide a self-centering jig which automatically locates a point in both the horizontal and the vertical directions, thereby eliminating the influence of the individual artisan in the location of holes or marks on a workpiece.
Another object of the present invention is to provide a self-centering which improves productivity by reducing the time required for accurately marking and/or drilling operations.